The process of manufacturing substrates for liquid crystal displays includes a number of steps in which glass sheets need to be supported and conveyed without damage to the sheet's major surfaces and, in particular, without damage to the sheet's “quality” surface upon which components of the display, e.g., thin film transistors and color filters, will be formed. For example, during the substrate manufacturing process, sheets need to be cut to size, edge ground, washed, and packaged and shipped or otherwise provided to the display manufacturer. Not only does the sheet need to be transported between the stations at which these steps are performed, but in some cases, the sheet also needs to be turned (rotated) during a step.
As sheet size has grown from a length of 1 meter to greater than 2 meters without a corresponding increase in sheet thickness, the lateral stiffness of the sheet has significantly decreased. At the same time, transport speed requirements have either remained constant or increased. Thus, the problem of transporting glass substrates for liquid crystal displays as it exists today can be described as trying to move a large glass sheet whose mechanical properties are not unlike those of tissue paper at high speed without touching the major surfaces of the sheet.
The present invention addresses this problem by providing non-contact bearings which eject a gas (e.g., air) against at least one of the sheet's major surfaces in patterns which stabilize the sheet and thus reduce the sheet's transverse movement during transport, i.e., the sheet's movement in a direction orthogonal to the direction of transport. In this way, large and thin sheets of glass can be safely transported at high speeds.